Abstract

G2 theory calculations were performed on [H3SiO4]−, H4SiO4, [H3AlO4]2−, [H4AlO4]−, and [H5AlO4]. Molecular structures, atomic charges, and infrared spectra at the HF/6-31G* and MP2/6-31G* levels are compared. The influence of polarization and diffuse functions on the structure of [H3SiO4]− is also examined. Basis set and electron correlation effects on potential energies are assessed by comparing various levels of theory. Proton affinities of these gas-phase molecules and related mineral surface species are predicted based on corrections for cluster-size effects.